Display systems are often used for displaying information in outdoor applications, such as e.g. for lighting or displaying such as in advertisement of for showing video or other information. Especially for outdoor applications, although not limited thereto, sealing of the electronics of the display system against ambient, i.e. environmental influence, and shading from other light sources typically is an important issue. A shader typically is used to block light from falling on the display system or the light source units thereof and to provide a black background which is non-reflective, e.g. in between the different light source units. Use of a shader typically results in an enhanced contrast and an improved image quality, e.g. for displaying a black image.
A first method to provide sealing and shading is to seal the electronics using a coating, e.g. a conformal coating, a silicone potting, etc. and to place a solid shader over the sealed electronics. The challenges with the first method is that because of the requirements of assembly and stability, the choice of shader materials is limited. Furthermore ideally, the shader should be rigid, environmentally curable, dark and non reflective. Polycarbonate or polyamide are the typical choice, but neither of these materials meet all the requirements.
Another, second, method to provide sealing and shading is to provide a solid shader that is integrated into the sealed assembly, leaving the cured sealing material, e.g. the silicone potting or conformal coating, exposed. The challenges of the first method also apply to the second method, wherein shaders that poke through the sealing material are used. Although the sealing material may be dark and mat, thus meeting some of the requirements for a good shader, the sealing material may pose an additional problem. The sealing material, such as e.g. silicone potting, is often not stable and over time it turns shiny. Additionally silicone is not mouldable, and it can therefore not be created with any specific texture or shape, e.g. light-trapping shape.
By way of example, a shader device being part of a display system is shown in cross section in FIG. 1. The display system 10 comprises a light source board 12, comprising a plurality of light source units 14, a heat path 16 and cooling plate 18 for cooling the device and a mounting stud 20 on which the light source board 12 is mounted. The system furthermore comprises a shading device 22 with upstanding shading parts 24, for shading the display system from direct light incidence. To seal the electronics, typically a sealing material 26 is applied, such as e.g. silicone. The edge of the display system may be masked using a black mask 28. The display system 10 shown in FIG. 1 furthermore comprises optical lenses 30 in front of the light source units 14.